early 14c., sobrenes, "state or character of being sober, moderation in desires or actions," from sober (adj.) + -ness. Also "gravity, seriousness" (late 14c.).
Entries linking to soberness
sober adj.
mid-14c., sobre, "moderate in desires or actions, habitually temperate, restrained," especially "abstaining from strong drink," also "calm, quiet, not overcome by emotion," from Old French sobre "decent; sober" (12c.), from Latin sobrius "not drunk, temperate, moderate, sensible," from a variant of se- "without" (see se-) + ebrius "drunk," which is of unknown origin.
The meaning "free from the influence of intoxicating liquors; not drunk at the moment" is from late 14c.; also "appropriately solemn, serious, not giddy." As "plain or simple in color" by 1590s. Jocular sobersides "sedate, serious-minded person" is recorded from 1705.
-ness
word-forming element denoting action, quality, or state, attached to an adjective or past participle to form an abstract noun, from Old English -nes(s), from Proto-Germanic *in-assu- (cognates: Old Saxon -nissi, Middle Dutch -nisse, Dutch -nis, Old High German -nissa, German -nis, Gothic -inassus), from *-in-, originally belonging to the noun stem, + *-assu-, abstract noun suffix, probably from the same root as Latin -tudo (see -tude).
sobriety n.
mid-15c., sobriete, "moderation in desires; temperate in indulgence," from Old French sobriete "sobriety, moderation" (Modern French sobrieté) or directly from Latin sobrietatem (nominative sobrietas) "moderation, temperance," from sobrius "not drunk, temperate, moderate, sensible" (see sober (adj.)). The meaning "steadiness, gravity" is recorded from 1540s. Soberness is older. Also earlier in Middle English was sobrete (c. 1300, from Old French) in the same sense, also "unintoxicated condition."